This graph shows the last two days query rates for each DNS server of the pool.ntp.org project. The long term graphs are available on the Munin page.

Put your cursor over a point in the graph to see the numbers for each server.

Drag to zoom in. Double-click to zoom out.

Change the number in the bottom-left box to set a moving average. (12=Hour average)

Many thanks to Dan Vanderkam for making such an awesome visualization tool!